1. Field of the Invention
This invention relates to transformers and more particularly to a transformer having a narrow profile for operation with an extremely high secondary winding current.
2. Background of the Invention
In the prior art, there are many types of transformers which have been designed for specific requirements of an electrical load. In many applications, a transformer must be specifically designed to meet certain physical space constraints while being able to provide the required power output to the electrical load. One example of a transformer specifically designed to meet certain physical space constraints is a narrow profile transformer. A narrow profile transformer has secondary winding output adapted to be received in a very narrow space and has the general appearance of a rectangular or square book.
In one example of an application for a narrow profile transformer is the connection of the secondary winding to an inductive electrical load. In this example, an inductor load comprising one or more turns is connected to the secondary winding of the narrow profile transformer for inductively heating a metallic part. The inductive heating of the metallic part is useful for heat treating the metallic part such as a bearing surface of the metallic part or the like. A series of narrow profile transformers can be placed in a side by side relationship for simultaneously induction heating a plurality of different bearing surfaces located on a long shaft such as the bearing surfaces of a crankshaft of an engine. The advantage of simultaneously induction heating a plurality of different bearing surfaces of a crankshaft of an engine should be readily appreciated by those skilled in the art.
U.S. Pat. No. 3,728,655 to Reinke discloses a narrow profile transformer that have been used extensively over the years for the simultaneous induction heating of all bearing surfaces of a crankshaft of an engine. Although the narrow profile transformer disclosed in U.S. Pat. No. 3,728,655 has been widely used in the industry, this transformer has many disadvantages. A primary disadvantage of the narrow profile transformer disclosed in U.S. Pat. No. 3,728,655 is the orientation of the secondary winding being interposed between two primary windings with the primary windings being connected electrically in series with one another. Accordingly, the narrow profile transformer disclosed in U.S. Pat. No. 3,728,655 suffered from high resistance and high leakage or stray inductance.
U.S. Pat. No. 2,862,195 to Kury discloses a transformer with a primary winding and a secondary winding being disposed in a aide by side relationship. This configuration of the primary and secondary windings similarly suffered from high resistance and high leakage or stray inductance.
Therefore, it is an object of the present invention to provide an improved narrow profile transformer with reduced resistance and reduced leakage or stray inductance.
Another object of this invention is to provide an improved narrow profile transformer with interleaved primary and secondary windings.
Another object of this invention is to provide an improved narrow profile transformer with a reduced width to make the narrow profile transformer as thin as possible.
Another object of this invention is to provide an improved narrow profile transformer wherein the primary winding is radially spirally wound with all portions of the primary winding intersecting a geometric plane extending through the improved narrow profile transformer.
Another object of this invention is to provide an improved narrow profile transformer wherein the secondary winding comprises a plurality of secondary turn elements being interleaved with the primary winding with all portions of the secondary winding intersecting the geometric plane extending through the improved narrow profile transformer.
Another object of this invention is to provide an improved narrow profile transformer with a reduced overall resistance of the primary winding and the secondary winding.
Another object of this invention is to provide an improved narrow profile transformer with the primary and secondary windings comprising conduits for directing the flow of a fluid coolant therethrough for cooling the primary and secondary windings.
Another object of this invention is to provide an improved narrow profile transformer incorporating a ferrite core for reducing core losses in the narrow profile transformer.
Another object of this invention is to provide an improved narrow profile transformer incorporating a ferrite core placed in relation to the primary and secondary windings enabling the fluid cooled primary and secondary windings to cool the ferrite core thus eliminating the need to independently cool the ferrite core.
Another object of this invention is to provide an improved narrow profile transformer which is encapsulated with a polymeric material for mechanically securing the primary and secondary windings relative to the core and for protecting the primary and secondary windings and the core.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed as being merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention with in the scope of the invention. Accordingly other objects in a full understanding of the invention may be had by referring to the summary of the invention, the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.